A mower of this general type is known which has a plurality of cutting elements guided in rotation on the upper face of a housing. The cutting element located at each end of the housing is surmounted by a rotary drum of a certain volume. The device for drivng the cutting elements and the rotary drums, and a part of the connecting elements which connect the cutting elements to the frame, penetrate inside the first drum by passing through its upper part. The other part of the connecting elements which connect the cutting elements to the frame penetrates inside the second drum by passing through its upper part. The latter connecting elements having a swivel bearing , so that the housing- connecting elements -frame assembly is not rigid. The housing can thus move to a certain extent in relation to the connecting elements and to the frame. This is important, given that the housing is in contact with the ground during work, and the ground can be very uneven.
Moreover, since the drums are made by forming and are fastened on the cutting elements by welding, it can happen that the upper part of the drums are offset in relation to the connecting elements.
Since the connecting elements are immobile and the drums inside of which at least a part of these connecting elements penetrate are rotary, it has been necessary to make, between the connecting elements and the upper part of the drums, a certain space to make possible, on the one hand, a certain movement of the housing and the drums in relation to the connecting elements and the frame, and, on the other hand, the rotation of the drums even if their upper part is offset in relation to the connecting elements.
When the known mower works, the two drums surmounting the outside cutting elements avoid the hooking of cut crop on the driving device and/or on the connecting elements. Additionally, the two drums windrow the cut crop to reduce the width of the windrow left by the mower. The crop which is moved by the drums rises along the drums, and a part of it penetrates inside the drums through the space made between the connecting elements and the upper part of the drums. Moreover, inside the drums are found crop seeds and earth.
Under the effect of the very high speed of the drums, the plant debris and the earth accumulate to form a very compact and relatively heavy mass. That heavy mass causes very great unbalancings of the mower. The unbalancings substantially increase the load on the bearings which guide, in rotation, the cutting elements that surmount the drums, as well as the load on the swivel bearing that has the connecting elements penetrating into the second drum. This reduces the service life of the bearings and the swivel bearing.
In addition, the accumulation of plant debris and earth forms a very abrasive mass which quickly wears out the connecting elements.
These phenomena are greater the larger the volume of the drums.